Polish top-level API #19
Comments
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Relevant comment from @davebryson in #15:
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Why is |
Yep, that's correct. If they aren't sorted/unique then the operations will cause UB.
The tree algorithms need to be able to binary search, and efficiently split the batch into two. This is theoretically possible with a b-tree structure although I don't believe it's possible with the built in |
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First thoughts on the signatures for the Merk top-level API: /// Create / Open
/// Where Database is a trait for storage
pub fn new(db: Arc<dyn Database>) -> Result<Merk> {}
/// Return the root hash
pub fn root_hash(&self) -> Option<Vec<u8>> {}
/// Get a value
pub fn get(&self, key: &[u8]) -> Result<Vec<u8>> {}
/// Visit key/values for a given range...
pub fn iter_range<F: FnMut(Node)>(&self, start: &[u8], end: &[u8], f: &mut F) -> Result<()> {}
/// Apply a batch of Put/Deletes, checking for sort and unique keys
/// I wonder if 'merge' may be better?
pub fn apply(&mut self, batch: &Batch) -> Result<()> {}
/// Apply a batch with no check
pub unsafe fn apply_unchecked(&mut self, batch: &Batch) -> Result<()> {}
/// Prove checking...
pub fn prove(&mut self, query: &[Vec<u8>]) -> Result<Vec<u8>> {}
/// Prove unchecked
pub unsafe fn prove_unchecked(&mut self, query: &[Vec<u8>]) -> Result<Vec<u8>> {}
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We could possibly make an API for building batches with something like: db.batch()
.put(vec![1], vec![1])
.put(vec![2], vec![2])
.delete(vec![3], vec![3])
.commit()?;This could use a |
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Yes. In fact that's what I did with an example app. It's basically a cache wrapper around Merk that uses BTreeMap. /// On Commit
/// BtreeMap => Batch
/// working_cache is a BTreeMap. StoreOp is used by BTreeMap to track dirty values
let mut batch: Vec<(&[u8], TreeOp)> = self
.working_cache
.iter()
.filter_map(|(k, storeop)| match storeop {
// Only update dirty 'puts'
StoreOp::Put(true, value) => Some((&k[..], TreeOp::Put(value.to_vec()))),
StoreOp::Delete => Some((&k[..], TreeOp::Delete)),
_ => None,
}).collect();
self.state.apply_unchecked(&mut batch).expect("Merk Commit:"); |
Not a lot of work has been put into making an ideal top-level API yet, so for a first release I'm just targetting one that's good enough, expecting to break it in a future release.
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